Video camera with variable image capture rate and related methodology

ABSTRACT

A camera with a selector device that may be used for adjusting frame rate while capturing video; and associated subsystems and methodologies.

BACKGROUND

Digital video cameras are devices that produce digital image datarepresentative of a period of time in a scene. As used herein ‘digitalvideo camera’ refers to any camera that generates such image data.‘Video’ as used herein refers generally to a series of frames andassociated timing information. The term video is used to refer to both avideo display, i.e. the display of streamed frames, and also to videodata, i.e. the digital information which may be stored or used toproduce a video display. The term ‘frame’ as used herein refers to asingle complete still image in a sequence of images that creates theillusion of motion within a scene when displayed in rapid succession(streamed). ‘Frame’ is also used to refer to digital informationrepresentative of the single still image. Frames within video areassociated with a brief period of time equal to 1/fps. The term ‘fps’ isan abbreviation for frames per second; as used herein, ‘fps’ refers tothe rate of video playback and/or recording speed of video.

A frame rate of 30 fps is often referred to in the art as ‘real-timespeed of video’ because it has a high enough fps that the video appears‘smooth’ to the human eye. For the Phase Alternating Line (PAL) standardestablished by the Nation Television Standards Committee adopted inEurope, the ‘full-motion rate’ is defined as 25 fps, each framecontaining 576 horizontal lines by 768 pixels (i.e., there are 25 framesin each second of video, resulting in each frame representing 1/25seconds of video). For the National Television Standard Committee (NTSC)standard adopted in America and Japan, the ‘full-motion rate’ is definedas 29.97 fps, each frame containing 480 horizontal lines by 640 pixels.A rate of 24 fps is generally considered acceptable for animation. At aslower rate of 12-15 fps, video appears ‘choppy’ to the human eye ifmoving objects are in the scene.

The video generated by a digital video camera may be transmitted to amemory device for storage or to an output device such as a video monitoror television that produces a replicated video of the sequential imagesof the scene.

Digital video cameras typically have optical elements, at least onetwo-dimensional photodetector array, a data storage device, a controllerand a display, all of which are generally mounted to a camera housing.Non-limiting examples of digital video cameras are described in thefollowing patents which are hereby incorporated by reference for allthat is disclosed therein: U.S. Pat. No. 6,097,879 of Komatsu et al.issued on Aug. 1, 2000 under the title VIDEO CAMERA APPARATUS OF DIGITALRECORDING TYPE and U.S. Pat. No. 5,343,243 of Maeda issued on Aug. 30,1994 under the title DIGITAL VIDEO CAMERA.

The digital video camera optical elements serve to focus an image of ascene onto the camera's two-dimensional photodetector array. The opticalelements typically comprise one or more lenses and/or reflectors. Thetwo-dimensional photodetector array generates image data representativeof the image of a scene imaged thereon. The controller serves to processthe image data and to transfer the image data to and from the datastorage device. The controller also serves to transfer image data to thedisplay and/or an output device. Additionally, the controller may serveto sequence this image data for playback at a later time to producevideo.

The two-dimensional photodetector array has a plurality ofphotodetectors typically arranged in closely positioned rows andcolumns. Each photodetector generates image data representative of asmall portion of the optical image of the object focused on thephotosensor array. The accumulation of image data generated by theplurality of photodetectors is representative of the entire image of thescene, similar to a mosaic representation of the image of the scene.Each photodetector outputs a data value which corresponds to theintensity of light it receives. The controller processes and arrangesthe image data generated by the plurality of photodetectors into acomplete set of image data often referred to as a frame of a video. Assequentially captured sets of image data are collected, stored and/orplayed, they produce video.

Digital video cameras process frames at a relatively high rate of speed.As previously discussed, the frames are recorded and/or played at aframe rate (e.g., 30 fps). Each frame and timing data associatedtherewith, when stored separately, may require a relatively small amountof memory. However, when frames are stored sequentially as video, thesequence of frames often requires a large amount of data. Storage ofthis video may consume memory reserves relatively quickly when the framerate is relatively high (e.g. 30 fps). Additionally, capturing,processing, storing and playing image data requires a significant amountof power. Portable digital video cameras have power supplies that havelimited power storage (e.g. batteries), therefore only a limited amountvideo capture may be completed before stored power is depleted.

Conventional video cameras capture frames of video at a predeterminedframe rate. This predetermined frame rate is preset at the time ofmanufacture or set by the user as a one-time-event. This one-timesetting of the frame rate occurs prior to capturing video. Suchone-time-event setting of frame rate may, for example, be at a lower fpssetting (e.g. 6 fps), a higher fps setting (e.g. 40 fps), or the usualsetting of about 30 fps. The lower fps setting is typically used inorder to conserve memory and power reserves. The relatively high fpssetting (e.g. 40 fps) is typically used in order to better capturescenes in which action occurs.

SUMMARY

In one embodiment, a camera user interface assembly may include: a videocapture selector having at least a first operating state in which thecamera captures image data at a first rate and a second user selectableoperating state in which the camera captures image data at a second ratedifferent from the first rate; the selector being switchable between thefirst and second states during continuous image data capture.

In another embodiment, a method of operating a camera may include:actuating a variable-frame-rate-trigger by variation of operation of atleast one operating parameter; determining a capture frame rate as afunction of the operating parameter; and capturing image data at thecapture frame rate.

In another embodiment, a method of operating a camera may include:actuating a variable-frame-rate-trigger with a first user input and inresponse thereto capturing a first plurality of images having a firstframe rate; actuating the variable-frame-rate-trigger with a second userinput, wherein the second user input is different from the first userinput and in response to the second user input capturing a secondplurality of images having a second frame rate, wherein the second framerate is dependent on the second user input, and the second frame rate isdifferent from the first frame rate; and storing the first and secondpluralities of images at the first frame rate and the second frame rate,respectively.

In another embodiment, a method of creating and displaying video of anobject may include: imaging the object on a photodetector array; inresponse to a first user input applied to a variable-frame-rate-trigger:generating a first image data set representative of the object; thenwaiting a first period of time, then generating a second image data setrepresentative of the object immediately after the first period of time;in response to a second user input applied to thevariable-frame-rate-trigger, wherein the second user input is differentthen the first user input: generating a third image data setrepresentative of the object; then waiting a second period of time, thengenerating a fourth image data set representative of the objectimmediately after the second period of time, wherein the second periodof time is different than the first period of time; streaming at leastthe first image data set, the second image data set, and streaming thethird image data set and the fourth image data set.

In another embodiment, a method of capturing image data with a cameramay include: determining a frame rate for future image capture basedupon a user input provided while the camera is simultaneously capturingimage data; then capturing further image data at the determined framerate; and storing the captured image data.

In another embodiment, a camera user interface may include: means forcapturing frames at a frame rate; means for selectively varying theframe rate while capturing the frames; and means for storing thecaptured frames.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear view of a camera.

FIG. 2 is a schematic cross-section, plan, schematic view of the camerataken across plane 2-2 of FIG. 1.

FIG. 3 is a flow chart showing certain features and operations of acamera.

DETAILED DESCRIPTION

FIG. 1 shows a digital video camera 100 having a housing 110. Thehousing 110 may have a front 112 (FIG. 2), a back 114, a left side 116,a right side 118, a top 120 and a bottom 122. The camera 100 may beprovided with a plurality of user interfaces such as, by way of exampleand not limitation, a mode button 124, a power button 126 and a zoomtoggle device 130 for operating the camera 100. The camera 100 alsoincludes a variable-frame-rate-trigger 128. The term‘variable-frame-rate-trigger’ as used herein means any selector devicethat may be used for adjusting a frame rate while continuously capturingvideo. The variable-frame-rate-trigger 130, sometimes referred to as a‘fps selector’ herein, may employ various types of selector mechanismsincluding, but not limited to, force detectors, pressure sensitiveswitches, speed sensors, displacement sensors, closed contact counters,azimuth position sensors, dials and other rotary devices such aspotentiometers, slide switching devices, or any other devices now knownor later developed that allows a user to control the frame rate of thecamera 100 through selective operation thereof based on selectiveoperation thereof. Additionally, it is noted that thevariable-frame-rate-trigger 128 is shown on the housing top portion 120.However, the variable-frame-rate-trigger 128 may be provided on otherportions of the camera 100 (e.g. housing front 112, housing left 116,housing right 118, etc.).

With reference to FIG. 2, the camera 100 may include a lens assembly132, a controller 134 and a photosensor array 136. The photosensor arrayis typically one or more two-dimensional arrays. When used for colorvideo the imaging light beam may be focused onto one photosensor arrayor may be split into multiple beams for generating multiple colorcomponent data sets by focusing the multiple beams onto a plurality ofphotosensor arrays. As used herein ‘photosensor array’ refers to bothsingle array and multiple array type photosensor assemblies. The camera100 can include other components such as a flash 138, a power supply140, a storage media interface 142 and a display 150. The lens assembly132 may be mounted to the camera housing front 112 in opticalcommunication with the photosensor array 136. Light passing through thelens assembly 132 forms an image of an object 160 on the photosensorarray 136. The controller 134 generates image data (also referred to asa frame of video) representative of the image of the object formed onthe photosensor array 136 in a manner previously described and wellknown in the art. A plurality of images generated in sequence by thecontroller 134 may be streamed together to generate video in a mannerdescribed later herein. The photosensor array 136 and other componentssuch as the flash 138, the power supply 140 and the storage mediainterface 142 may be placed in electronic communication with thecontroller 134 by conventional electronic interfaces such as conductorwires, circuit boards, etc.

As shown schematically in FIG. 3, the camera controller 134 may includean image processor 170 and a fps subroutine 172. The fps subroutine maybe an image capture algorithm. The image processor 170 and the fpssubroutine 172 may be components operationally associated with thecontroller 134 or embedded within the controller 134. In the event thatthe image processor 170 and the fps subroutine 172 are embedded in thecontroller 134, they may be firmware or software operationallyconfigured within the controller 134. The controller 134 may furtherinclude a video output subroutine 174. The video output subroutine 174may process the image data provided by the image processor 170 in amanner directed by the fps subroutine 172. Such processing of the imagedata by the video output subroutine 174 may dictate the frame rate atwhich the individual frames of the video are sent to output devices(e.g. media storage interface 142, display 150, or other output devicesthat are now know to those skilled in the art or that are laterdeveloped).

With continued reference to FIG. 3, the variable-frame-rate-trigger 128may be operated by a user to vary the frame rate of video while video isbeing captured. In one embodiment, the user's finger 180 applies adifferent amount of force ‘F’ to the variable-frame-rate-trigger 128select different frame rates. Such different frame rates are representedas video capture 1 ‘C1’, video capture 2 ‘C2’, video capture 3 ‘C3’,video capture 4 ‘C4’, video capture 5 ‘C5’ and video capture 6 ‘C6’. Inthis schematic representation, the individual video captures (e.g. C1,C2, C3, C4 . . . ) span equal periods of time (e.g. 1 second).Therefore, assuming the illustrated time periods of the video capturesare equal and 1 second in duration, the frame rate of capture C1 is 11fps, the frame rate of capture C2 is 31 fps, the frame rate of captureC3 is 15 fps, the frame rate of capture C4 is 7 fps, the frame rate ofcapture C5 is 6 fps and the frame rate of capture C6 is 17 fps. Theseexemplary frame rates are provided as non-limiting examples of framerates that may be implemented in a particular camera. Those skilled inthe art will appreciate that relatively slower (e.g. 1 fps) orrelatively faster (e.g. 100 fps) frame rates could be implemented. Thepossible selections could be discrete step amounts or could becontinuously variable.

The schematic representation of frame rate capturing of video shown inFIG. 3 illustrates that the camera 100 may be operated via thevariable-frame-rate-trigger 128 to capture faster video (e.g. videocapture C2) or slower video (e.g. video capture C5). A user may beprovided with feedback to inform him/her of his/her selected rate suchas variable pressure, audible clicks associated with discrete speeds, avariable speed beep proportionate to the selected speed, a variablepitch, or other audio signal associated with different speeds.Additionally, the user may be provided with feedback in the form ofindicia displayed on the camera display 150 or other sensory feedback asthose skilled in the art will appreciate upon reading the presentdisclosure.

As shown in FIG. 3, the video provided by the video output subroutine174 may be played on an output device such as a television 182. Videoplayed on the television 182 may play at a constant playback speed ‘S’.When played at the constant playback speed S, the playback frame ratevaries as a function of the capture frame rate. In the exemplaryscenario provided in FIG. 3, if captures C1, C2, C3, C4, C5 and C6 areplayed back in sequence, the video is 6 seconds in duration. A total of87 frames are played back during this six second video. During the firstsecond, 11 frames are shown on the television 182. During the secondsecond, 31 frames are shown. During the third second, 15 frames areshown. During the fourth second, 7 frames are shown. During the fifthsecond, 6 frames are shown. And, during the sixth second, 17 frames areshown. With this six second long video, some portions of the videocontain more frames then other portions (e.g. the 2^(nd) second of videocontains 31 frames, while the 5^(th) second of video contains 6 frames).Therefore, some portions of the video contain more detail (e.g. thesecond second, capture C2) than other portions of the video (e.g. thefifth second, capture C5).

Having described exemplary features of one embodiment of a camera 100having a variable-frame-rate-trigger 128, the operation thereof will nowbe described in further detail.

With reference to FIG. 2, at the outset a user may desire to capturevideo of a scene. In this exemplary scenario, the scene is a picturesquemountain scene 160 having at least one object therein that moves (e.g. abird flying from a nest in a tree). The user may depress the powerbutton 126 in order to ‘turn-on’ the camera 100. The user may theninvoke a variable frame rate video capture mode by depressing modebutton 124. While in the variable frame rate video capture mode, theuser may direct the video camera 100 to capture video at varying framerates via the variable-frame-rate-trigger 128.

The user prepares for video capture by pointing the video camera at thescene 160, thereby imaging the scene 160 onto the photosensor array 136through the lens assembly 132. To capture video, the user depresses thevariable-frame-rate-trigger 128 with his/her finger 180 at a force ‘F’.The video camera 100 captures video at a frame rate dependent, in thisembodiment, on the magnitude of the force F.

In this exemplary scenario, the user may witness a bird sitting in anest (not shown) within the mountain scene 160. Assuming that relativelylittle action is occurring in the scene 160, the user may desire tominimize memory and power usage. Therefore, the user requires arelatively slow frame rate (e.g. 5 fps) of video. In order to capturethe slow frame rate of video, the user pushes thevariable-frame-rate-trigger 128 with a force F of F1. While capturingthis video at the relatively slow frame rate, the user notices that asecond bird (not shown) has entered the scene 160 and is flying at ahigh speed. The user desires to capture this flying bird and is willingto expend memory and power in order to capture the event. The user maythen increase the force F to F2 (i.e., F1 is less then F2) exerted byhis/her finger 180 onto the variable-frame-rate-trigger 128. Byincreasing the force F to F2, the variable-frame-rate-trigger 128receives the user's directive to notify the fps subroutine 172 of theuser's desire to increase the frame rate of the video capture. The fpssubroutine 172 determines the capture rate that correlates to themagnitude of the force F (e.g. F2). In this exemplary scenario, thesecond bird is simply flying around the scene 160, therefore the userdesires only a slight increase in frame rate (e.g. 15 fps). During thisperiod, video is captured at the slightly increased frame rate while theuser maintains the force F2 exerted on the variable-frame-rate-trigger128. While capturing the video at the slightly increased frame rate, theuser notices that the first bird appears to be preparing to fly from thenest to meet the second bird. The user desires to capture this event ingreat detail. An increase in the frame rate will increase this detail.Therefore, the user increases the force F exerted on thevariable-frame-rate-trigger 128 to a third force F3 (i.e. F1 is lessthen F2, which are both less then F3). By increasing the force F to F3,the frame capture rate is increased to a higher rate (e.g. 40 fps). Theuser may continue this increased force F until the event is thoroughlyrecorded, ceases to exist, or if the memory or power supply is depleted.This video may be viewed immediately on an output device such as display150 or television 182, or may be stored on a device such as the storagemedia device 142 for later viewing. The described trigger is ‘relativelyprogressively actuatable’ meaning that as the actuating parameter, inthis case force ‘F’, is progressively changes the fps is alsoprogressively changed.

Another exemplary use of camera 100 is in the capture of sporting events(e.g. baseball). For example, a user may record a pitcher pitching abaseball towards a batter. The user may direct the camera to recordrelatively minimal detail (i.e. slow fps) while the pitcher prepares tothrow the pitch. However, just before the baseball is thrown, the usermay direct the camera to record a relatively detailed video (i.e. highfps). Such variance in the frame rate of the video capture is controlledby the user via the variable-frame-rate-trigger 128 in a dynamic mannerwhile recording video and thus does not require the user to stoprecording, reset the speed, and possibly entirely miss the pitch or thewind up as would be likely if he/she were using a conventional videocamera.

While illustrative and presently preferred embodiments of the inventionhave been described in detail herein, it is to be understood that theinventive concepts may be otherwise variously embodied and employed andthat the appended claims are intended to be construed to include suchvariations except insofar as limited by the prior art. For example,although a camera with a single selector for both initiating videocapture and selecting the frame rate thereof has been specificallydescribed it would be appreciated by those skilled in the art that thesefunctions could be performed with multiple buttons or switches ratherthan one. For example, a central button could be used to activate videocapture at a normal speed and a ring around the button could be rotatedin one direction to increase speed and in another direction to decreasespeed.

1. A camera user interface assembly comprising: a video capture selectorhaving at least a first operating state in which said camera capturesimage data at a first rate and a second user selectable operating statein which said camera captures image data at a second rate different fromsaid first rate; said selector being switchable between said first andsecond states during continuous image data capture.
 2. The assembly ofclaim 1 wherein said selector is relatively progressively actuatable. 3.The assembly of claim 2 wherein said selector operates through variationof at least one operating parameter, said at least one operatingparameter comprising at least one of: switching time, force magnitude,displacement speed, amount of displacement, number of closed contacts,azimuth position and potentiometer resistance.
 4. The assembly of claim1 wherein said selector operates through variation of at least oneoperating parameter, said at least one operating parameter comprising atleast one of: force magnitude, displacement speed and number of closedcontacts.
 5. The assembly of claim 1 wherein said selector operatesthrough variation of the operating parameter comprising force magnitude.6. The assembly of claim 1 and further comprising: feedback of selectionof said first rate or said second rate.
 7. The assembly of claim 6wherein said feedback comprises at least one of: audio notification andvisual notification.
 8. A method of capturing image data with a cameracomprising: determining a frame rate for future image capture based upona user input provided while the camera is simultaneously capturing imagedata; then capturing further image data at said determined frame rate;and storing said captured image data.
 9. A camera user interfacecomprising: means for capturing frames at a frame rate; means forselectively varying said frame rate while capturing said frames; andmeans for storing said captured frames.
 10. The camera user interface ofclaim 9 and further comprising: means for notifying of said frame rate.11. A method of operating a camera, said method comprising: causing saidcamera to initiate image data acquisition by actuating a switch locatedon the exterior of said camera; causing said camera to vary the framerate at which image data is acquired by selectively operating saidswitch; and wherein said causing said camera to vary the frame rate atwhich image data is acquired occurs while said camera is acquiring imagedata.
 12. The method of claim 11 and further comprising: causing saidcamera to stop image data acquisition by discontinuing actuation of saidswitch.
 13. The method of claim 11 wherein said selectively operatingsaid switch comprises applying a varying force to said switch.
 14. Themethod of claim 13 and further wherein: increasing the level of forceapplied to said switch causes said frame rate to increase.